1. Technical Field
The present disclosure relates to an image display device that is suitable to mount on a moving body such as a vehicle.
2. Description of the Related Art
In recent years, an image display device which is called a head-up display has been developed, and has been mounted on a moving body such as a vehicle. In the head-up display to be mounted on a vehicle, light modulated according to image information is projected toward a wind shield, and vehicle driver's eyes are irradiated with reflected light from the wind shield. Consequently, a vehicle driver can see a virtual image of an image ahead of the wind shield. For example, a vehicle speed, outdoor temperature or the like is displayed as a virtual image. Recently, displaying a navigation image or an image which calls attention to a passerby as a virtual image has also been studied.
In the above-described head-up display, a laser light source such as a semiconductor laser can be used as a light source for generating a virtual image. In this configuration, while laser light is modulated according to an image signal, a screen is scanned with the laser light. In the screen, the laser light is diffused and an area of light with which vehicle driver's eyes are irradiated is widened. Consequently, even when a vehicle driver slightly moves the head, the eyes do not go out of the irradiation area, and the vehicle driver can favorably and stably see an image (virtual image).
Unexamined Japanese Patent Publication No. 2009-150947 describes a configuration of moving a screen in an optical axis direction and changing a virtual image formation position in a front-back direction. In this configuration, the screen is driven by using a motor, a feed screw and a rack.